 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.internal.ide.dialogs;

 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.Preferences;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.preference.PreferencePage;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Label;
 import org.eclipse.ui.IWorkbench;
 import org.eclipse.ui.IWorkbenchPreferencePage;
 import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.internal.ide.IDEWorkbenchMessages;
 import org.eclipse.ui.internal.ide.IIDEHelpContextIds;

 /**
  * Preference page for linked resources.
  * This preference page allows enabling and disabling the workbench linked
  * resource support.
  * It also shows all path variables currently defined in the workspace's path
  * variable manager. The user may add, edit and remove path variables.
  *
  * @see org.eclipse.ui.internal.ide.dialogs.PathVariableDialog
  */
 public class LinkedResourcesPreferencePage extends PreferencePage implements
         IWorkbenchPreferencePage {
     private Label topLabel;

     private PathVariablesGroup pathVariablesGroup;

     /**
      * Constructs a preference page of path variables.
      * Omits "Restore Defaults"/"Apply Changes" buttons.
      */
     public LinkedResourcesPreferencePage() {
         pathVariablesGroup = new PathVariablesGroup(true, IResource.FILE
                 | IResource.FOLDER);

         this.noDefaultAndApplyButton();
     }

     /**
      * Resets this page's internal state and creates its UI contents.
      *
      * @see PreferencePage#createContents(org.eclipse.swt.widgets.Composite)
      */
     protected Control createContents(Composite parent) {
         Font font = parent.getFont();

         PlatformUI.getWorkbench().getHelpSystem().setHelp(parent,
                 IIDEHelpContextIds.LINKED_RESOURCE_PREFERENCE_PAGE);
         // define container & its gridding
 Composite pageComponent = new Composite(parent, SWT.NULL);
         GridLayout layout = new GridLayout();
         layout.marginWidth = 0;
         layout.marginHeight = 0;
         pageComponent.setLayout(layout);
         GridData data = new GridData();
         data.verticalAlignment = GridData.FILL;
         data.horizontalAlignment = GridData.FILL;
         pageComponent.setLayoutData(data);
         pageComponent.setFont(font);

         final Button enableLinkedResourcesButton = new Button(pageComponent,
                 SWT.CHECK);
         enableLinkedResourcesButton.setText(IDEWorkbenchMessages.LinkedResourcesPreference_enableLinkedResources);
         enableLinkedResourcesButton.setFont(font);
         enableLinkedResourcesButton
                 .addSelectionListener(new SelectionAdapter() {
                     public void widgetSelected(SelectionEvent e) {
                         boolean enabled = enableLinkedResourcesButton
                                 .getSelection();
                         Preferences preferences = ResourcesPlugin.getPlugin()
                                 .getPluginPreferences();
                         preferences.setValue(
                                 ResourcesPlugin.PREF_DISABLE_LINKING, !enabled);

                         updateWidgetState(enabled);
                         if (enabled) {
                             MessageDialog
                                     .openWarning(
                                             getShell(),
                                             IDEWorkbenchMessages.LinkedResourcesPreference_linkedResourcesWarningTitle,
                                             IDEWorkbenchMessages.LinkedResourcesPreference_linkedResourcesWarningMessage);
                         }
                     }
                 });

         createSpace(pageComponent);

         topLabel = new Label(pageComponent, SWT.NONE);
         topLabel.setText(IDEWorkbenchMessages.LinkedResourcesPreference_explanation);
         data = new GridData();
         data.verticalAlignment = GridData.FILL;
         data.horizontalAlignment = GridData.FILL;
         topLabel.setLayoutData(data);
         topLabel.setFont(font);

         pathVariablesGroup.createContents(pageComponent);

         Preferences preferences = ResourcesPlugin.getPlugin()
                 .getPluginPreferences();
         boolean enableLinking = !preferences
                 .getBoolean(ResourcesPlugin.PREF_DISABLE_LINKING);
         enableLinkedResourcesButton.setSelection(enableLinking);
         updateWidgetState(enableLinking);
         return pageComponent;
     }

     /**
      * Creates a tab of one horizontal spans.
      *
      * @param parent the parent in which the tab should be created
      */
     protected static void createSpace(Composite parent) {
         Label vfiller = new Label(parent, SWT.LEFT);
         GridData gridData = new GridData();
         gridData = new GridData();
         gridData.horizontalAlignment = GridData.BEGINNING;
         gridData.grabExcessHorizontalSpace = false;
         gridData.verticalAlignment = GridData.CENTER;
         gridData.grabExcessVerticalSpace = false;
         vfiller.setLayoutData(gridData);
     }

     /**
      * Disposes the path variables group.
      * @see org.eclipse.jface.dialogs.IDialogPage#dispose()
      */
     public void dispose() {
         pathVariablesGroup.dispose();
         super.dispose();
     }

     /**
      * Empty implementation. This page does not use the workbench.
      *
      * @see IWorkbenchPreferencePage#init(org.eclipse.ui.IWorkbench)
      */
     public void init(IWorkbench workbench) {
     }

     /**
      * Commits the temporary state to the path variable manager in response to user
      * confirmation.
      *
      * @see PreferencePage#performOk()
      * @see PathVariablesGroup#performOk()
      */
     public boolean performOk() {
         return pathVariablesGroup.performOk();
     }

     /**
      * Set the widget enabled state
      *
      * @param enableLinking the new widget enabled state
      */
     protected void updateWidgetState(boolean enableLinking) {
         topLabel.setEnabled(enableLinking);
         pathVariablesGroup.setEnabled(enableLinking);
     }
 }

